[vv_]

After reading your post, I went looking for good C/C++ implementations suitable for embedded development, and honestly, I couldn’t find many! MQTT is typically straightforward to implement, so most companies develop their own version to better adapt to the specific systems they use for data transmission. That said, maybe this is an opportunity to create a well-designed MQTT client implementation tailored specifically for embedded devices! :)

[accelbred]

I work for the team that maintains coreMQTT (https://github.com/FreeRTOS/coreMQTT)

Its a C89 MQTT library intended for embedded devices.

[tcshit]

There is a very nice MQTT client C++ implementation that works great on embedded devices too. As it so happens, it is right now under formal review for inclusion into Boost. It is called async-mqtt5 and can be found at: https://github.com/mireo/async-mqtt5/